First-Principles Study on Chromium-Substituted α‑Cobalt Oxyhydroxides for Efficient Oxygen Evolution Reaction

Owing to their catalytic, electronic, and optical properties, metal hydroxides are extensively used in energy applications. Despite recent progress, the synthesis of monolayer metal hydroxides with unique structures remains a challenge, and their potential use in the oxygen evolution reaction (OER) has not been fully investigated. Herein, the fabrication of chromium-substituted α-cobalt hydroxide through a simple co-precipitation method under optimum conditions at higher pH is described. Such nanostructures can competently catalyze oxygen evolution reactions to produce a current density of 10 mA cm^–2 at an overpotential of 240 mV in alkaline medium. Microscopic, electrochemical, and spectroscopic analyses reveal that the exceptional OER performance originates from thin monolayer sheets with exposed active sites and partially due to the substitution of α-CoOOH with Cr. The phase purity is highlighted through powder X-ray diffraction (PXRD), energy-dispersive X-ray (EDX) mapping, and X-ray photoelectron spectroscopy (XPS) analysis.